1. Field of the Invention
This invention relates generally to magnetic heads in disk drives, and more particularly to magnetic write heads having yoke structures with notches formed directly adjacent pole tip structures.
2. Description of the Related Art
A write head is typically combined with a magnetoresistive (MR) read head to form a merged MR head, certain elements of which are exposed at an air bearing surface (ABS). Traditionally, a write head includes first and second pole pieces connected at a back gap behind the ABS. The first and second pole pieces have first and second pole tips, respectively, which are separated at the ABS by a non-magnetic write gap. An insulation stack, which comprises a plurality of insulation layers, is sandwiched between the first and second pole pieces, and write coil layers are embedded in the insulation stack. A processing circuit is connected to the write coil for conducting write current through it which, in turn, induces magnetic write fields in the first and second pole pieces. Magnetic write fields of the first and second pole tips fringe across the gap layer at the ABS. In a magnetic disk drive, a magnetic disk is rotated adjacent to and a short distance (fly height) from the ABS so that the write fields magnetize the disk along circular tracks. The written circular tracks then contain information in the form of magnetized segments with fields detectable by the MR read head.
Modern inductive write heads for writing on perpendicular media require a greater magnetic flux gradient to achieve higher areal density recording. This increased magnetic flux gradient is necessary in order to reduce the amount of side writing and adjacent track interference (ATI). This gradient may also affect the on-track linear density of bits on the perpendicular media. One type of write head which provides such an increased magnetic gradient includes a return yoke having a “trailing shield” located upstream from the pole tip. When making such a write head with a sub-micron dimension pole tip, it is important that no excessive amount of magnetic write flux at the pole tip be shunted away through the trailing shield and the return yoke. A major challenge in producing a write head with a trailing shield is to magnetically connect the trailing shield to the return yoke so as to limit the amount of magnetic write flux that can be drawn directly into the return yoke at the pole tip region.
Accordingly, what are needed are improved magnetic write heads with increased magnetic flux gradients and methods of making the same.